Pump runner assembly



Nov. 26, 1940. o. JAcoBsE-N.

PUMP RUNNER ASSEMBLY Filed Feb. 23, 1939 Ovsrsm 'Jkcoasm,

Patented Nov. 26, 1940 UNITED STATES PATENT OF-FlCE PUMP RUNNER ASSEMBLYOystein Jacobsen, Montgomery County, Ohio, as!

signor to The Duriron Company,

Inc., Dayton,

I Ohio, a corporation of New York Application February 23, 1939, SerialNo. 257,978

3 Claims.

an acid or water containing acid, it is usual to,

fabricate the runner or impeller out of high'silicon iron which has beenfound to resist corrosion. This metal is somewhat brittle and isextremely hard to machine, which facts introduce a severe problem insecuring the shaft to the runner. The latter revolves at a high rate ofspeed, e. g., 1800 revolutions per minute, so that it is absolute- 1ynecessary that the shaft be rigidly afiixed to the runner and tomaintain this connection'even when the pump is being subjected tovariable loads. It is apparent that the slightest wearor tendency forthe shaft to move with respect to the runner would soon result inconsiderable looseness due to the small lever distances through whichthe shaft exerts its rotative effort on the impeller.

The prior art has evolved certain modes ofconnection between the shaftand the impeller,

which has withstood the severe strains exerted at" the point where theshaft connects with the impeller, but such connections have not had aconsiderably long life, particularly when the pump was working undervariable loads, variable heads and variable speeds, and more especiallywhen the impeller was large, heavy and its inertia considerable. It willbe understood that it is impossible to use bolts or other positivesecuring means, because the impeller material does not lend itself tomachine working.

The primary object of the present invention is to provide an improvedmechanical connectionwhich is of simple and sturdy design and adapted tosecure a steel shaft to a disk of corrosionresisting material carried onthe end of the shaft, thus providing an assembly which can be rotated athigh speeds and under variable loads.

Another object is to provide a positive lock between the runner of acentrifugal pump and its shaft, permitting the assembly to be driven ineither direction without slippage under the strains introduced at thetime the impeller is being started and also preventing unscrewing of theshaft when the pump is started up backwards.

A still further object is to provide a bond between the impeller andshaft, not only as against rotation between members when the impeller issubjected to considerable inertias or momentums,

but also as against relative longitudinal movement between the impellerand the shaft. 1

The invention will be better understood when reference is made to thefollowing description and the accompanying-drawing.

Figure 1 is a longitudinal section of a pump assembly, partlybrokenaway, and showing the drive pulley and shaft in elevation.

Figure 2 is an enlarged section of aportion of the impeller and shaftshowing the improved manner in which these elements are securedtogether. y Figure 3 is a cross section taken along line 3-3 of Figure 2and looking inthe direction of the arrows. I

Figure 4 is a cross section taken along line 44 in Figure 2 and lookingin the direction of. the arrows, I f I Referring to the drawing indetail, numerals I and 2 .designate the frontand back platesrespectively of a pump housing containing an im-' peller of the openrunner type. The back plate 2 terminatesin a horizontal sleeve 3 whichextends away from the plate and takes on a cylindrical configuration toform a housing forpacking material. The plate 2 is provided with' a pairof sealing rings 4 against which the solid or plateportion 5 of theimpeller bears. An opening 40, is provided to drain off the fluid whichgets by these rings. There is a plurality of vanes o'r blades 6, eitherof arcuate or straight configuration, secured to the front side of theimpeller plate 5. These'vanes are shown in elevation in Figure 1,because the line of section does not pass therethrough. As will be notedfrom Figure ;l the front plate I of the housing terminates in acylindrical member 1' provided with an opening 8 which serves as the eyeor the inlet passage for the impeller.

The plate 5 of the impeller is provided. with a nosepr humped portion 9which extends into theopening 8 and serves to direct the liquid whichpasses through the opening into the passages (not shown) betweenthe-vanes 6. There" are projecting from the other side of the plate 5; anumberof cylinders or hubs of different diam-.

peller are cored out .to leave a compartment in-- dicated at M. which,as will be explained hereinafter, contains a machinabl metal, suchasbronze, white metal or the like, positioned by a I I pores of thepacking are filled with grease in any cupwhich is adapted to forcegrease under pressure through the opening l8 in the housing 3 castingoperation. Between the sleeve l l and the housing 3, there is a quantityof packing material I5 which preferably takes the form of rings so as toaccommodate themselves to the cylinders of different sizes and theserings are clamped together in any suitable manner, for example, by

,a flanged plate It which slides along'the sleeve II and is adapted toexert longitudinal pressure against the packingi By moving the plate "5to the right, it is obvious that the packing IE will press downwardly onthe sleeve II to form a liquid tight joint. The

suitable manner and, as illustrated, there is pro vided a nozzle l1leading to an adjustable grease and through openings in the partitionmember I 9 to the packing.

The shaft for rotating the impeller is indicated at and is provided atone end with a screw portion2l and at the other end a portion 22 oflarger diameter, to which a pulley 23 is keyed. This shaft is madepreferably of machinable steel designed to carry heavy rotating loads atconsiderable speedl Thereis thus a shoulder indicated-at 24 formedbetween the portion 22-and anfannularcon'ipartment which receives greaseor other lubricant through the opening in the housing 28 when the .plug.30 is removed.

- Asstated hereinbefore, the present invention is concerned moreespecially with the difficult problem of obtaining a positive looking orsecuring means between the screwed end of the shaft and-,the impeller.The manner in which the improved locking arrangement is effected isbestshownin Figures 2, 3 and 4. The inner or lefthand end of the bronzemember I4 is providedwith. a number of milled slots 3], .five as shownin Figure 4, these slots having a depth along the axis of the. shaft ofapproximately /4" and a width of about the same dimension. The slotsvv3|" are preferably equidistantly spaced around the bronze member andeach slot is -pre'- sented to the, threaded opening in the member.

The shaft 28 is provided with a pair of oppositely positioned, elongatedkeyways 32 of. considerably, greater width than the width ofeach slot3lfand extending on each side of the righthand bearing surface l2.- Aswill be noted in Figure 2, the milling of the keyways begins at a.position considerably to the left of the bearing surface I2 andterminates at a position near the deeper surface of the slots 3|. Aswill also be noted inFigure 2, there is an annular space left betweenthe lefthand end of the bronze member i4 and the righthand edge of theshoulder formed by the bearing portion l2.

"Keyways 33, similar to keyway 32, are also provided at 'apositiondetermined by the shoulder ar e that part of the keyway 33 is cut in thelarge diameter portion 22 of the shaft and the remainder of the keywayis cut in the small diameter portion 20 of the shaft. The purpose ofthese keyways will be explained presently.

In order to assure that the bronze member l4 does not turn within thecored hub member I0, I provide four or more ribs 34 which projectinwardly toward the shaft and are made integral,

"a horizontal position so that the sleeve ll remains upright andthen'pouri'ng the bronze or other fusible metal through the opening inthe sleeve until it collects in the cored compartment within the hub 10.The molten metal will obviously fill up all the'spaces between the ribs34, as indicated in Figure 3. When sufiicient metal has thus beenintroduced, the latter is permitted to solidify and a hole is bored intothe metal and threaded to receive the threaded end of the shaft 20.However, before the threads are actually cut, the keyways 3! areprovided by an end miller and shaper, the lefthand end of the bronzemember l4 being also milled to the proper length at the same time.During this machining operation, the bearing surfaces l2 are ground verycarefully so as snugly to receive the shaft portion 20.

Assuming that the keyways 32 and 33 have been cut in the shaft, thelatter is then introduced into the sleeve l l and the end of the shaftis screwed into the threaded opening provided in the bronze member I4.The shaft is threaded intothis opening to such a depth that the 'sh0ul-.

der on the shaft 22 firmly abuts the lefthand end of the sleevel l.

Molten metal, for example, lead or Babbitt, is then introduced into thekeyways 3| and 32 toprevent the shaft from turning with respect to thebronze member and thus lock the shaft in position. This metal isindicated at its various positions by the reference character 35. Forpouring the locking metal, the assembly is held with the shaft invertical position and is heated to insure against freezing of the metalduring the pouring operation. One of the keyways 33 adjacent theshoulder 24 is utilized as the inlet in pouring, a suitable funnel gatebeing applied to facilitate the operation. The metal, thus supplied,flows downward between the shaft and the sleeve H, filling all ofthespa'ces therebetween, including the annular space between the bearing-surfaces l2, the keyways 3|, 32 and also the annular spaceimmediately to the left of the keyways. The keyway 33' at the shoulder24 which lies in opposition to the one through which pouring occurs,merely acts as an escape passage for air or gases during the pouringoperation, thus facilitating the free inflow of the metal.

'When the assembly cools, the locking metal solidifies, and anyunscrewing action of the shaft with respect to the bronze member I4 ispositively prevented due to the locking effect of the metal in the twosets of keyways 3|, 32, the one lying in the bronze member l4 and theother in the shaft 20. The arrangement also'gives assurance that thekeyways 3| which are overlapped by the keyway 32 will be filled withfusible metal, since the combined depth of the two keyways permits amuch more ready flow of the molten metal than is the case with those ofthe keyways 3i whose sole source of supply is the blades 6, as indicatedby the arrows, and emerges from the periphery of the blades to bedelivered to a volute chamber which communicates with 15 an air orseparation chamber (not shown).

During operation, it is apparent that heat is developed at the varioussurfaces which contact with the impeller, such as the sealing rings 4and to some extent at the packing I5 which is 20 compressed against thesleeve H in order to constitute a water-tight joint. Friction may alsobe produced at the bearing surfaces on the member l3 and at the surface3'! which forms part of annular ledge against which the packing iscompressed. Since the impeller revolves at a high rate of speed, thetemperature of the immediate parts may become greatly elevated, and thusfacility for the transference of this heat to cool the metal parts mustbe provided. This heat unless quickly dissipated may cause the sleeve IIto bulge in the middle, 1. e., due to the longitudinal stress introducedby the shoulder 24, and this bulging effect might cause additional heatto be developed at the packing and at other bearing surfaces.

It has been found that the poured metal which fills the elongatedannular space between the bearing surfaces 12 acts as an excellentmedium to transfer heat from the sleeve II to the large 0 metal mass ofthe shaft which is at a considerably lower temperature. It will beunderstood that this annular space must be provided in order that theentire inner surface of the sleeve need not be grotmd to fit the shaft-alaborious and very expensive job. Consequently, unless this space werefilled with the metal 35, there would be a cylindrical body of airpositioned between the shaft and the sleeve which would preclude inconsiderable degree the ready transfer- 50 ence of heat between thesleeve and the shaft.

Thus, the poured metal not only provides a locking means between theshaft and the bronze member 54, but in addition furnishes an allmetalpath for heat which might otherwise accumulate in the sleeve II to bedistributed and readily dissipated by the shaft.

It has been pointed out that the shaft is positively locked in themember M. It is also apparent that, by reason of the ribs 34 and the 60fact that the bronze member I4 is cast around these ribs, the member [4is securely locked Within the cored hubs I0.

From the foregoing, it is evident that I have provided an improvedconstruction by which a shaft of steel is firmly secured to an impellermade of an acid-resisting metal and which is not readily machinable. Thelocking arrangement is obtained solely by successive casting operationsand is so effective that, regardless of the direction in which the heavyimpeller is started, the shaft positively cannot turn with respect tothe member 54 and the latter is firmly secured to the impeller.

While I have shown only four ribs 34 projecting into the member l4, itis obvious that any number of ribs may be employed and having anydesired shape. These ribs may be cast within the hub member by the samecoring operation which provides the compartment.

It will be understood that I desire to comprehend within my inventionsuch modifications as come within the scope of the claims and theinvention.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

1. In combination, a fluid impeller of acid-resisting, hard-to-machinemetal and a steel shaft, said impeller having'a hollow hub containingsolidified fusible material, a shaft screwed into said fusible material,means for preventing the unscrewing of the shaft in said material, andmeans for preventing rotation of the fusible material with respect tosaid impeller whereby said shaft is prevented from rotating and movinglongitudinally with respect to said impeller.

2. In combination, a fiuid impeller of acid-resisting, hard-to-machinemetal and a steel shaft, said impeller having a hollow hub ofcylindrical configuration and containing cast metal, a shaft screwedinto said cast metal, means for preventing the unscrewing of the shaftin said cast metal, and means for preventing rotation of the cast metalwith respect to said impeller whereby said shaft is prevented fromrotating and moving longitudinally with respect to said impeller, saidlast-mentioned means comprising interlocking projections which extendradially inwardly and outwardly from said hub and said cast metalrespectively.

3. In combination, a rotatable member and a shaft adapted to be securedthereto, said member having a hollow hub containing fusible materialsolidified in situ and bored for receiving the end of the shaft, meansfor anchoring said shaft to said fusible material, and internal ribs onsaid hub for preventing rotation of the fusible material with respect tosaid member whereby the shaft is prevented from rotating and movinglongitudinally with respect to said member.

OYSTEIN J ACOBSEN.

